| HS Code | 549278 |
| Product Name | Polymer Grade VAM MEHQ 10–15 ppm |
| Chemical Name | Vinyl Acetate Monomer |
| Cas Number | 108-05-4 |
| Molecular Formula | C4H6O2 |
| Molecular Weight | 86.09 g/mol |
| Grade | Polymer Grade |
| Purity | ≥99.9% |
| Mehq Inhibitor Content | 10–15 ppm |
| Appearance | Clear, colorless liquid |
| Odor | Low odor, ester-like |
| Boiling Point | 72.7 °C |
| Melting Point | -93 °C |
| Flash Point | -8 °C (closed cup) |
| Specific Gravity | 0.932 at 20 °C |
| Viscosity | 0.43 mPa·s at 20 °C |
| Refractive Index | 1.3953 at 20 °C |
| Vapor Pressure | 115 hPa at 20 °C |
| Water Solubility | 20 g/L at 20 °C |
| Acidity As Acetic Acid | ≤0.02% |
| Water Content | ≤0.05% |
| Color Apha | ≤5 |
As an accredited Polymer Grade VAM MEHQ 10–15 ppm (Low-Odor Interior VAE Emulsion) factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Polymer Grade VAM MEHQ 10–15 ppm supplied in 1,000 kg IBC totes or 200 kg drums, sealed for low-odor stability. |
| Container Loading (20′ FCL) | Load 20' FCL with Polymer Grade VAM MEHQ 10–15 ppm VAE emulsion in sealed drums/IBCs; secure, ventilate, avoid contamination. |
| Shipping | Ship as a stable, non-hazardous aqueous emulsion in sealed, corrosion-resistant containers. Protect from freezing, excessive heat, and UV exposure. Use standard industrial handling with adequate ventilation, spill containment, and grounding during transfers. Avoid ignition sources and prolonged skin contact. No special transport classification required, but follow safe chemical shipping protocols. |
| Storage | Store in tightly sealed original containers in a cool, dry, well-ventilated area away from heat, sparks, open flames, and direct sunlight. Maintain temperature above freezing; avoid excessive heat. Ensure MEHQ inhibitor (10–15 ppm) remains effective by preventing oxygen starvation. Keep away from incompatible materials, oxidizers, and polymerization initiators. Rotate stock to prevent prolonged storage. |
| Shelf Life | Shelf life is typically 12 months when stored sealed at 5–35°C, protected from freezing and direct sunlight. |
Interior architectural coatings formulated with VAE binders derived from polymer-grade vinyl acetate monomer containing hydroquinone monomethyl ether at 10–15 ppm are specified where residual monomer and coalescent demand must remain low under GB 18582-2020 and Directive 2004/42/EC Annex IIA Phase II limits. A typical high pigment volume concentration flat wall formulation is compounded in a high-speed disperser equipped with a Cowles blade operated at 18–25 m/s tip speed; the grind phase contains water 15–25 wt%, sodium polyacrylate dispersant 0.3–0.8 wt%, nonionic wetting agent 0.1–0.2 wt%, mineral oil defoamer 0.2–0.5 wt%, titanium dioxide 8–15 wt%, calcium carbonate 20–35 wt%, and talc 5–10 wt%. The letdown phase receives VAE dispersion at 12–18 wt% dry binder, with pH adjusted to 4.5–5.5 using ammonia or sodium hydroxide; coalescent demand is held at 0–1.0 wt% because the ethylene content depresses minimum film-forming temperature to 0–5 °C. Rheology is set with a high-shear associative polyurethane thickener at 0.3–1.2 wt%, and the terminal product is a low-odor interior matt emulsion paint tested under ISO 11998-1 for wet scrub resistance and under EN 13300 for classification. Grind fineness is controlled below 25 µm on a Hegman gauge because coarse particles reduce scrub performance and create batch-to-batch sheen variation. Residual vinyl acetate monomer is monitored by headspace gas chromatography; low-odor interior specifications commonly control residual vinyl acetate below 1000 ppm and free formaldehyde below 10 ppm in the as-supplied VAE dispersion.
Within resilient flooring and engineered wood assembly, VAE dispersions produced from low-MEHQ vinyl acetate monomer are compounded into wet-set and pressure-sensitive adhesives where long open time and low indoor air emissions are specified. The compounding sequence in a planetary or butterfly mixer loads the VAE dispersion at 30–50 wt%, then adds calcium carbonate filler at 20–45 wt%, dibenzoate ester plasticizer at 0–5 wt%, mineral oil or silicone defoamer at 0.1–0.3 wt%, and an alkali-swellable or associative rheology modifier at 0.2–1.0 wt%. High-speed disperser blades are avoided after the emulsion is loaded because prolonged shear can destabilise carboxylated VAE particles; instead, low-speed planetary agitation at 10–30 rpm under a vacuum of −0.08 MPa removes entrained air. Open time is adjusted through the ratio of associative thickener to ethylene content in the binder and is validated by wet-tack testing; published data for this specific configuration is limited, so production trials on trowel-applied resilient flooring adhesives remain the accepted validation route. The terminal product is a low-odor adhesive for luxury vinyl tile, sheet vinyl, or engineered wood flooring, tested for hazardous substances under GB 18583-2008 and for low emissions under an interior emission-class certification such as EC1 Plus. Seven-day bond strength at 23 °C and 50 % RH is evaluated by ASTM D6862 peel testing, while compatibility with cementitious subfloors is assessed by alkali resistance after contact with fresh concrete or levelling compound.
For tufted carpet lines, the effect is tied to particle packing and the shear-thinning character of VAE dispersions. A precoat compound is typically built at filler loadings of 200–400 phr calcium carbonate per 100 phr of VAE emulsion, with sodium polyacrylate dispersant at 0.1–0.4 phr, a cellulosic or associative co-thickener at 0.2–1.0 phr, and a defoamer at 0.05–0.2 phr to control air entrainment. In the production-scale make-down tank, a high-shear sawtooth disperser is used for the filler slurry, but the VAE binder is added after the slurry has cooled below 35 °C through a static mixer or low-speed sweep blade; adding the emulsion at high temperature or under intense shear can cause coagulation on the tank wall. At filler loading above 300 phr, low-shear viscosity rises sharply, but the shear-thinning response under knife-over-roll can become excessive, causing pick-up variation; the thickener package is therefore split into high-shear and low-shear components to maintain roller pick-up without sacrificing wet lay-down. The compound is applied by a knife-over-roll coater at 300–800 g/m² wet add-on to the tufted primary backing, then dried through a tenter-frame oven with zone temperatures from 120 °C to 150 °C; residual alkalinity from calcium carbonate must be controlled because it can hydrolyse vinyl acetate ester linkages and generate acetic acid odor. The finished carpet tile or broadloom product is tested by ASTM D5116-17 small-chamber emission testing for TVOC and formaldehyde under the Carpet and Rug Institute Green Label Plus programme. Viscosity is maintained at 5000–15000 mPa·s at 20 rpm using a Brookfield RV spindle 5.
Because interior acoustic panels are installed in enclosed plenum spaces, the binder system must limit aldehyde release and resist sag during thermal curing. In air-laid nonwoven processes, VAE dispersion is applied by spray or foam to a formed web of polyester, glass, or cellulose fibre at a dry add-on of 8–20 wt%; the binder is diluted with deionised water to 15–25 % solids. For low-odor acoustic panels, N-methylolacrylamide-based self-crosslinking is excluded, and only formaldehyde-free crosslinker systems are accepted. The impregnated web passes through a three-zone oven at 110–150 °C, with residence time of 60–180 s; when the web exceeds 150 °C, the VAE film can yellow and release acetic acid. Final acoustic panels are tested under ISO 16000-6 for TVOC and under ASTM E1333 for formaldehyde emissions, with specification ceilings aligned to chamber test protocols. The terminal products include ceiling tiles, wall absorber panels, and office partition cores; the dry film binds fibre intersections and provides flexural rigidity without the brittle failure observed with high-Tg binders. Process control on the production line includes monitoring binder add-on by near-infrared sensors and measuring compression recovery of the finished panel at 25 °C under 50 % strain.
Cementitious and gypsum-based skim coats and wall levelling compounds are modified with VAE dispersions at polymer-to-binder ratios of 0.05–0.20 by dry binder weight. The mixing sequence in a forced-action mortar mixer dry-blends calcium carbonate, white cement, or gypsum with cellulose ether at 0.2–0.6 wt%, then adds water containing the VAE emulsion and a polycarboxylate superplasticizer; mixing speed is held below 300 rpm because air entrainment from the surfactant system, rather than the residual inhibitor in the emulsion, is the primary processing variable. The final paste is applied by trowel at 1–3 mm thickness, and retempering with additional water is limited because the VAE film forms during the first drying cycle and redispersion is incomplete. For interior use, the levelling compound is tested for pull-off adhesion by ISO 4624:2016 using a 20 mm steel dolly after 7 days of conditioning, with failure in the substrate rather than at the interface considered acceptable. Chemical emission testing is conducted under GB 18582-2020 for volatile organic compounds and formaldehyde. The terminal product is low-odor wall levelling paste that accepts latex primer and paint after 24–48 h at 23 °C and 50 % RH.
As a low-MFFT binder, VAE derived from monomer with MEHQ at 10–15 ppm is post-added to interior primer formulations after the pigment grind stage. Interior primers and sealers require adequate penetration into porous gypsum and concrete substrates while leaving a surface that topcoats can bond to. A typical formulation uses VAE dispersion at 15–30 wt%, titanium dioxide 8–12 wt%, calcium carbonate 15–25 wt%, water 25–35 wt%, and film-forming or thickening additives at 0.5–2.0 wt%. The finished primer is applied by airless spray at 0.8–1.2 mm tip orifice and 120–180 bar pressure; dry film build after application is 25–50 µm. Pull-off adhesion after 7 days at 23 °C is measured by ISO 4624:2016; adhesion failure within the porous mineral substrate rather than at the primer interface is considered acceptable. The product is tested for formaldehyde and TVOC under GB 18582-2020 and, where applicable, meets Directive 2004/42/EC subcategory limits for interior primers. The terminal product is a low-odor water-based interior primer and sealer for new gypsum board, previously painted mineral surfaces, and trowelled levelling compounds.
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Polymer-grade vinyl acetate monomer (VAM, CAS 108-05-4) inhibited with methyl ether of hydroquinone (MEHQ) at 10–15 ppm is a raw-material control grade for the synthesis of low-odor interior vinyl acetate-ethylene (VAE) copolymer emulsions. The product is specified as Polymer Grade VAM MEHQ 10–15 ppm (Low-Odor Interior VAE Emulsion). The grade designation does not refer to a finished emulsion; it identifies the monomer quality and inhibitor level that permit reproducible nucleation and low residual monomer after semicontinuous emulsion polymerization in glass-lined or stainless-steel reactors. Under ASTM D2190-07, the material falls within polymer-grade vinyl acetate limits, but the 10–15 ppm MEHQ window is narrower than the general polymer-grade allowance, which is a deliberate control for low-odor interior binders. In a 10 m³ glass-lined batch reactor with a retreat-curve impeller, a precharge containing MEHQ at 15 ppm and ammonium persulfate at 0.35 wt% on total monomer typically shows an induction period of 18–25 min at 65 °C before the exotherm rises above 1 °C/min. The same grade at 10 ppm shortens the induction period to 10–15 min. This assay-dependent delay requires initiator feed, ethylene pressure, and jacket cooling to be tied to the actual inhibitor assay rather than to a fixed time clock.
Typical low-odor interior VAE binders produced from this monomer have solids of 54–56 mass %, pH of 4.5–5.5, Brookfield viscosity of 500–2500 mPa·s at 23 °C, and residual VAM below 0.1 mass %. Viscosity is measured by ISO 2555; residual VAM is determined by headspace gas chromatography. The monomer is not the sole determinant of these values; reactor configuration, ethylene pressure, and post-stripping initiator contribute equally.
Acceptable material at the reactor feed line has a water mass fraction below 0.05 %; water above 0.1 % inhibits ethylene incorporation in VAE polymerization through chain transfer and can produce lower film tensile strength at equivalent ethylene pressure. Acidity as acetic acid is maintained at or below 0.005 % to limit hydrolysis of vinyl acetate during storage and to keep the final emulsion pH stable without excessive ammonia or sodium bicarbonate adjustment. Aldehyde controls are part of the low-odor specification; acetaldehyde is measured in the monomer because it is a major odor-active residue in VAE interior coatings and can survive ordinary emulsion stripping.
| Parameter | Sale limit | Test procedure |
|---|---|---|
| Appearance | Clear, colorless liquid, no suspended matter | ASTM D2190-07 |
| VAM purity by gas chromatography | ≥ 99.9 mass % | ASTM D2190-07 |
| MEHQ content | 10–15 ppm | Monomer-specific gas chromatography with flame ionization detection |
| Water | ≤ 0.05 mass % | ASTM D1364-95 |
| Acidity as acetic acid | ≤ 0.005 mass % | ASTM D1613-06 |
| Color | ≤ 5 Pt-Co | ASTM D1209-05 |
| Distillation range | 72.0–73.5 °C at 101.3 kPa | ASTM D1078-11 |
| Aldehydes as acetaldehyde | ≤ 100 ppm | Supplier headspace gas chromatography method |
| Peroxide index | ≤ 10 ppm as hydrogen peroxide | Supplier titration specification |
The aldehyde ceiling of 100 ppm is not a general ASTM D2190-07 requirement but is applied to this low-odor grade because acetaldehyde partitions into the aqueous phase and survives emulsion strippers, producing a sweet or acrid smell in interior topcoats. Water above 0.1 mass % is a practical failure point in VAE polymerization because water in the monomer phase increases hydrolysis of VAM to acetaldehyde and acetic acid during storage and can act as a chain-transfer impurity during ethylene incorporation.
VAE emulsion production with this monomer is typically operated in a semicontinuous mode at 60–90 °C and 0.5–6 MPa ethylene pressure. The monomer is fed under nitrogen pressure, and the reactor is sparged with nitrogen until dissolved oxygen is below 0.5 ppm. Oxygen and MEHQ together are radical scavengers; oxygen is usually the larger variable because its solubility in the aqueous phase changes with pressure and temperature. A 10 m³ stainless-steel reactor with an anchor agitator at 50–70 rpm and a jacket cooling capacity of 300 kW can experience an exotherm delay of 10–25 min when the initial charge contains MEHQ at 15 ppm and residual oxygen at 0.5 ppm. Reducing MEHQ to 10 ppm with the same oxygen level typically advances the exotherm by 5–10 min. Batch records indicate that the delay is not directly proportional to MEHQ concentration across all initiator systems; potassium persulfate at 0.4 wt% and sodium formaldehyde sulfoxylate as a redox pair at 55 °C can be more sensitive to MEHQ than ammonium persulfate alone at 80 °C.
Ethylene incorporation is affected by reactor pressure; for an interior low-odor VAE with minimum film formation temperature near 0 °C, ethylene mass fraction in the copolymer typically falls between 10 % and 25 % based on total polymer solids. At ethylene pressures below 3 MPa, the incorporation rate is mass-transfer limited; at pressures above 6 MPa, the reactor approaches the safety limits of standard glass-lined vessels. The monomer grade contributes to low odor primarily by preventing the formation of acetaldehyde and peroxide-derived species during storage rather than by changing ethylene incorporation.
The practical consequence for low-odor interior VAE is that residual VAM must be driven below 0.1 mass % by a combination of high conversion, post-polymerization initiator, and vacuum stripping. Inhibitor that remains in the monomer feed can extend the final conversion plateau; however, at normal feed rates, it does not need to be removed because the continuous addition of initiator overwhelms the small MEHQ flow. If the monomer feed assay drifts from 10 ppm to 15 ppm, an operator can adjust the initiator feed rate by 5–8 % or extend the post-cook by 15–30 min to maintain the same residual VAM. In 12 m³ pilot reactors, replacing an uninhibited or low-inhibitor VAM with this grade without adjusting initiator feed has resulted in a residual VAM increase of 200–500 ppm after a fixed 4 h cook; adjustment of the final persulfate dose to 0.15 wt% reduced residual VAM to below 0.1 mass % after vacuum stripping.
In interior architectural coatings, the value of this VAM grade is realized primarily through the finished VAE binder’s residual monomer, aldehyde, and odor profile. Low-odor is not equivalent to low-VOC; a binder can pass VOC limits by ISO 11890-2 while still carrying odor-active traces of acetaldehyde, ethyl acetate, or VAM at parts-per-million levels. The monomer specification therefore includes controls for water, acidity, and aldehyde precursors that are not always present on a general polymer-grade certificate. For interior wall paints regulated under GB 18582-2020 or evaluated for indoor emissions according to ISO 16000-6, the use of MEHQ-inhibited VAM at 10–15 ppm reduces the probability of discoloration from inhibitor oxidation relative to hydroquinone-inhibited grades, although published comparative sensory data for this specific monomer grade is limited.
Interior topcoats formulated with VAE binders from this monomer are applied at wet film thickness of 150–250 µm and dried at 23 °C and 50 % RH; the low-odor property is assessed after 24 h and 28 days in chamber tests. Residual VAM above 0.05 mass % in the dried film can produce an acrid note that panelists detect before VOC analysis shows a failure. Film tensile properties should be confirmed by ASTM D638-14 after any monomer replacement; ethylene content shifts of 1–2 % can change elongation and dirt pickup. The monomer’s acetaldehyde ceiling of 100 ppm becomes important in formulated paints that are stored in closed containers for 6–12 months; acetaldehyde can form during storage and is released on opening.
Compared with general hydroquinone-inhibited polymer-grade VAM, the MEHQ-inhibited grade is selected when the emulsion is intended for white or pastel interior paints because hydroquinone oxidation products can contribute yellowing under light exposure. Compared with uninhibited VAM, the product does not require refrigerated trucks or immediate use; it can be held in nitrogen-blanketed carbon steel tanks for 12 months at 25 °C without forming peroxide levels above 10 ppm. Compared with VAM grades inhibited at 3–5 ppm MEHQ, the 10–15 ppm range gives better stability during long ocean freight and tank transfer but adds a measurable induction period in low-temperature redox initiation. In thermally initiated formulations at 80 °C, the difference in initiator demand between 10 ppm and 15 ppm MEHQ is often less than 3 %; in redox formulations at 55 °C, batch records show initiator demand differences of 5–10 %.
| Grade | Inhibitor | Typical inhibitor level | Ambient storage stability | Polymerization response | Downstream fit |
|---|---|---|---|---|---|
| Polymer Grade VAM MEHQ low-odor interior VAE | MEHQ | 10–15 ppm | 12 months at 25 °C | Induction period 10–25 min at 65 °C | Low-odor low-color interior VAE binders |
| General polymer-grade VAM with hydroquinone | Hydroquinone | 3–8 ppm | 6–12 months | Stronger aqueous-phase inhibition; may require higher initiator | General emulsions and polyvinyl alcohol systems |
| Uninhibited VAM | None | None | 7–14 days at 25 °C | Negligible induction; peroxide risk | Immediate-use or cold-chain polymerization |
| Low-inhibitor MEHQ VAM | MEHQ | 3–5 ppm | 3–6 months | Lower induction; less stable in long storage | Specialty low-inhibition polymerizations |
Storage conditions are part of the product specification. MEHQ is consumed slowly by oxygen; in a carbon steel tank with a nitrogen pad at 5–20 kPa, the inhibitor loss at 25 °C is typically 1–3 ppm over six months. If the tank breathes air through a conservation vent, MEHQ loss can reach 5–8 ppm in the same period, and peroxide formation can begin before the inhibitor is fully depleted. Storage above 30 °C accelerates VAM hydrolysis to acetaldehyde and acetic acid, especially when water is present at 0.1 mass %. The product should not be stored in direct sunlight, near steam coils, or in unlined carbon steel with active rust, because iron corrosion products can initiate radical polymerization at the metal surface. Pumps and transfer lines should be flushed with nitrogen before service, and copper or copper alloys should be avoided. If a shipment has been exposed to 40 °C for more than 48 h, the inhibitor assay and peroxide index should be checked before use; material above 15 ppm MEHQ may require a proportioning strategy to avoid excessive induction, while material below 10 ppm MEHQ with a peroxide index above 10 ppm should not be stored further.
Moisture and acid excursions also create boundaries. At water content above 0.15 mass %, the monomer should be dried or segregated for non-emulsion uses; in VAE polymerization, water above this level can produce enough acetaldehyde during storage to affect odor. The material is incompatible with oxidizing agents, strong acids, and free-radical initiator solutions. Spill containment should use non-sparking tools and avoid drains, because VAM is flammable and polymerizes violently in contact with concentrated acids or peroxides.
